The European Union blacklisted two Turkish nationals as retaliation over Ankara’s energy drilling off Cyprus in a move that has more political symbolism than economic punch, Bloomberg reports.

Relations between the EU and Turkey have been deteriorating since Turkish President Recep Tayyip Erdogan responded to a failed coup attempt in mid-2016 by unleashing a widespread crackdown on political opponents.

Ties soured further in 2018 when the Turkish navy prevented drilling by Italy-based Eni SpA in Cypriot waters and again late last year, when Turkey carried out a military operation in northern Syria to carve out a buffer zone and struck a controversial accord with Libya on their maritime boundary.